Low capacity fuse and method of making the same



May 31, 1932. E. v. SUNDT LOW CAPACITY FUSE AND METHOD OF MAKING THESAME Filed Sept. 9 1929 INVENTOR E Kdu/zdi" BY WRZ ATTORN EYxS' PatentedMay 31, 1932 UNITED STATES PATENT OFFICE EDWARD Vr SUNDT, 0F QHIOAGO,ILLINOIS LOW CAPACITY FUSE AND METHOD OF MAKING THE SAME Applicationfiled September 9, 1929.

constructed that it will fuse readily at the passage of a small amountof current therethrough.

Other objects and advantages will appear in the following specification,and the novel features of the invention will be particularly pointed outin the appended claims.

My invention is illustrated in the accom- 'panying drawings, formingpart of this application, in which Figure 1 is an illustration of a fusewire ready to be assembled,

Figure 2 is a sectional view of the casing showing the fuse wiredisposed therein,

Figure 3 illustrates the assembling of a ferrule upon the end of thecasing, and

Figure 4 is a side elevation of the fuse as assembled, a portion thereofbeing shown in section.

In carrying out my invention I provide a fuse wire 1 which is of highresistance material, such as nickel chromium or copper nickel alloy. Thewire 1 is metal plat-ed throughout its length as at 2 with the exceptionof the central portion indicated generally at 3. This central portion isshielded during the plating. A highly combustible material 4, such asphosphorus mixed with a suitable binder, is disposed upon the barecentral portion 8 of the wire 1. F

' The wire 1 in this condition is then placed in a casing 5 which isconstructed of any suitable insulating material, preferably glass. Theends of the wire are bent over the edges of the casing 5 so as to holdthe wire in place. It willbe observed that the wire ex- Serial No.391,375.

tends at an angle through the casing. A ferrule such as that indicatedat 6 is placed upon one end of the casing over the adjacent end of thewire. A quantity of solder is placed in the casing upon the ferrule asindicated at 55 7 in Figure 3. The solder 7 is melted, thus firmlysecuring the ferrule, the wire, and the casing together. In a likemanner, another portion of solder is placed within the casing andanother ferrule is placed upon the other 69 end of the casing andsecured in place by melting the solder. In this manner the fuse isassembled.

When the fuse is disposed in a circuit, the

current will flow through the ferrules and the fuse wire connectingthese ferrules. WVhen the current is higher than desired for the devicesin which the current is used, the wire 1 will become heated. Thecombustible material 4 requires little heat to become ignited and willtherefore become ignited before the wire will become fused. Upon theignition of this combustible material, the wire will be instantaneouslyfused. This is one of the outstanding features of this invention;namely, the provision of a fuse by means of which a circuit may beinstantaneously broken upon the reception of a higher current thandesired.

Another feature of the invention is the metal plating of the wire 1which reduces the heat generated by the fuse to a minimum, since only asmall portion of the fuse wire becomes heated the maximum degree. Thisbrings about an instantaneous fusing which is necessary in many cases.

I claim:

1. A fuse construction comprising a tubular member provided withconstricted end portions, a fuse wire disposed in said tubular member,said fuse wire being provided with end formations for gripping the endsof the tubular member whereby the fuse member is held in a suspendedposition therewithin, cap

members disposed over the ends of the tubuthe ends of the fuse wire, andthe cap members therein.

2. A fuse construction comprising a tubular member, a fuse wire disposedin said tubular member, said fuse wire being provided with endformat-ions for gripping the ends of the tubular member whereby the fusewire is held in a suspended position therewithin, cap members disposedover the ends of the tubular member and provided with openingstherethrough, and fusible solids disposed within the ends of the tubularmembers and adapted for being heated whereby said solids may be fusedfor embedding the ends of the tubular member, the ends of the fuse wire,and cap members therein.

3. A fuse construction comprising a tubular member, a fuse wire disposedin said tubular member, said fuse wire being provided with oppositelyextending hook formations for gripping the ends of the tubular member,cap members disposed over the ends of the tubular member and providedwith openings therethrough, and fusible solids disposed within the endsof the tubular member, said solids when fused extending through theopenings in the cap members whereby the ends of the tubular member, theends of the fuse wire, and the cap members may be embedded therein.

4. Afuse construction comprising a tubular member provided withconstricted end portions, a fuse member disposed in the tubular memberand provided with end formations for gripping the ends of the tubularmember, cap members disposed over the ends of the tubular member, andmeans for embedding the constricted end portions of the tubular member,the ends of the fuse wire, and the cap members.

5. A fuse construction comprising a tubular member provided withconstricted end portions, a fuse wire disposed in said tubular member,said fuse wire being provided with formations for grippng the ends ofthe tubular member whereby the fuse wire may beheld in a suspendedposition therein, cap members disposed over the ends of the tubularmember and provided with openings therethrough, and fusible solidsdisposed within the ends of the tubular members whereby said solids,when heated, may be fused for imbedding the constricted end portions ofthe tubular member, the ends of the fuse wire, and the cap memberstherein.

6. A fuse construction comprising a tubular member provided withconstricted end portions, a fuse wire disposed in said tubular member,said fuse wire being provided with oppositely extending hook formatonsfor gripping the ends of the tubular member, and cap members disposedover the ends of said tubular member and provided with open ingstherethrough and fusible solids disposed Within the ends of the tubularmember, said solids when fused extending through the openings in the capmembers whereby said cap members, the constricted end portions of thetubular member, and the end portions of the fuse wire may be imbeddedtherein.

Signed at Chicago in the county of Cook and State of Illinois this 27thday of August,

EDWVARD V. SUNDT.

